MicroRNA-299-3p as a potential marker of tumor size in non-small cell lung cancer.

Background: Lung cancer is one of the world's leading causes of cancer-related death. A tumor biopsy is the gold standard for diagnosis but may not be representative of the whole tumor. We therefore need non-invasive biomarkers to guide us in structure, mass, prognosis and treatment. Therefore, alternative non-invasive and dynamic biomarkers are needed to assist physicians in evaluating tumor structure, histology, burden, prognosis, and treatment response. Telomerase dysregulation is key to cancer development. MicroRNAs can be both tumor suppressors and oncogenes. Bioinformatic analyses suggest that microRNA-299-3p interacts with telomerase. This study evaluated serum levels of microRNA-299-3p before and after surgery in patients with non-small cell lung cancer (NSCLC) and explored their potential association with tumor size. Methods: This observational pilot study included 15 NSCLC patients who underwent anatomical lung resection at a specialist hospital, following a power analysis. Blood samples were collected before and three weeks after surgery. MicroRNA was isolated using kits according to the manufacturer's protocols. Patients who had received chemotherapy or radiotherapy, had multiple primary cancers, or did not give informed consent were excluded. Results: There was no significant difference in miRNA-299-3p levels between preoperative and three-week postoperative serum samples. However, a significant negative correlation was identified between preoperative miRNA-299-3p levels and tumor size (r=-0.59; p=0.02). Conclusion: Preliminary findings suggest that levels of the molecule RNA-299-3p are linked to tumour size. It is thought that lower levels of RNA-299-3p may counteract the effect of telomerase, which can cause uncontrolled cell growth. More research is needed to confirm these results.